1. Field of the Invention
This invention relates to a handle lock for a handle operated electrical switching apparatus and, more particularly, to such a handle lock for locking a movable handle in the OFF position of the apparatus. The invention also relates to an electrical switching apparatus, such as a circuit breaker, including a handle lock.
2. Background Information
Electrical switching apparatus include, for example, circuit switching devices and circuit interrupters such as circuit breakers, contactors, motor starters, motor controllers and other load controllers.
Circuit breakers are generally old and well known in the art. Circuit breakers are used to protect electrical circuitry from damage due to an overcurrent condition, such as an overload condition or a relatively high-level short circuit condition.
Circuit breakers used in residential and light commercial applications are commonly referred to as miniature circuit breakers because of their limited size. Such circuit breakers typically have a pair of separable contacts opened and closed by a spring biased operating mechanism. A thermal-magnetic trip device actuates the operating mechanism to open the separable contacts in response to persistent overcurrent conditions and to short circuits. Usually, circuit breakers of this type for multiple circuits within the residence or commercial structure are mounted together within a load center or panelboard, which may be located in a basement or other remote location.
Some electrical switching apparatus, such as circuit breakers, have padlock hasps associated with the operator handle whereby a padlock may be attached through the hasp in a position to block movement of the operator handle from one operating position to an opposite operating position. Thus, a worker working on equipment in a line controlled by the apparatus can disconnect electrical power from the line and be assured that it will not be reconnected until the padlock is removed from the apparatus. The hasps of the apparatus generally accept one or more padlocks having shackles to allow individual workers to apply their respective padlocks.
A device popular with workers is a safety lockout, which may be attached to the hasp of the apparatus. The safety lockout has provisions to receive up to six padlocks. The safety lockout is a scissors-like device made from a pair of flat hardened steel plates, hinged at approximately the center, to provide a pair of openable jaws, which close and overlap through the hasp. Handle portions of each plate have six holes, which respectively align when the device is closed so that the jaws overlap. Shackles of padlocks may be inserted through any of the aligned six holes to prevent opening of the safety lockout and removal thereof from the apparatus. A problem with the safety lockout is that the flat, two-piece shackle is narrower and thinner than the padlock shackle. When used in a hasp that can accommodate a plurality of padlock shackles, the safety lockout shackle can be moved and twisted to a position wherein it is ineffective to block the movement of the operator handle.
U.S. Pat. No. 5,467,622 discloses a molded case circuit breaker having an auxiliary operator mechanism attached thereto. A security hasp is provided for the handle operator by providing an upstanding flange having an opening, which is sized and shaped to receive up to three padlock shackles simultaneously. Locking the padlock to the hasp by inserting the padlock shackle through the flange opening secures the padlock in a position interfering with movement of the operator handle, thereby blocking movement of the handle from one operating position to an opposite operating position. An auxiliary plate is pivotally mounted to the flange. The plate may be stored in an adjacent position, to one side of the flange opening. When it is desired to use a safety lockout or a padlock, the plate is pivoted wherein the plate covers the opening in the flange. The plate has a round hole for a single padlock which aligns near a top edge of the flange opening and near an edge of such opening that is closest to the operator handle in the OFF position. The plate also has an elongated opening that is similarly aligned with the flange opening, and overlaps the edge of such opening closest to the operator handle. The elongated opening receives the thin flat cross-section portion of a shackle of a safety lockout and maintains that shackle properly oriented to block movement of the operator handle to the opposite operated position.
U.S. Pat. No. 5,817,999 discloses a circuit breaker operating handle locking device which selectively keeps the circuit breaker operating handle locked and prevented from moving between OFF and ON positions. A locking arm selectively engages the circuit breaker operating handle in either of the OFF and ON positions. A locking bracket passes through a narrowed locking section of the locking arm and past a lock-receiving hole in the bracket. The lock-receiving hole has an asymmetric portion for receiving a safety lockout device, such as the one available from Hoffman Engineering Company of Anoka, Minn. as Catalog Number A-SL6. This allows the locking device to accommodate a number of security locks or a security lock having a hasp, which is larger than the lock-receiving hole. The security lock prevents pivotal movement of the locking arm. Longitudinal movement of the locking arm is prevented by the circuit breaker operating handle wedging the locking arm against one end of a cut-away groove. The asymmetric portion of the lock-receiving hole is positioned away from the mounting plate so that when a gangling arrangement is positioned on the device it does not obstruct the mechanism.
It is known to employ a handle lockoff bracket including a plate secured on the front face of a circuit breaker. Disposed on the plate is a flange, which has a D-shaped opening that accepts the shackles of one or more padlocks, in order to maintain the handle of the circuit breaker in its OFF position.
There is room for improvement in handle lock devices and in circuit breakers employing the same.
This need and others are satisfied by the invention, which is directed to a handle lock device that functions with ganged (e.g., handle-tied) multiple pole circuit breakers as well as single pole circuit breakers. The handle lock device accepts either a padlock or a scissor lock.
As one aspect of the invention, a handle lock device for a movable operator handle of an electrical switching apparatus is operable with a shackle of a safety lockout device and alternatively operable with a shackle of a padlock. The handle lock device comprises: a member adapted for securement to the electrical switching apparatus; a flange on the member adapted for positioning alongside the movable operator handle of the electrical switching apparatus; and an opening in the flange, the opening adapted to receive only one shackle and having a perimeter which includes first opposing portions adapted to receive the first cross section of the shackle of the safety lockout device and to restrain rotation of the first cross section within the opening, with the shackle of the safety lockout device blocking movement of the movable operator handle from a first position to a second position thereof, the perimeter also includes second opposing portions adapted to alternatively receive a different second cross section of the shackle of the padlock with the shackle of the padlock blocking movement of the movable operator handle from the first position to the second position thereof.
The safety lockout device may be a scissor lock including locking members having the first cross section, which is a rectangular cross section having two opposing ends, and the first opposing portions of the perimeter of the opening may be adapted to restrain the ends of the rectangular cross section. The different second cross section of the shackle of the padlock may be a circular cross section, and the second opposing portions of the perimeter of the opening may be adapted to alternatively receive the circular cross section.
The first cross section may be a generally rectangular cross section, and the different second cross section may be a circular cross section. The perimeter of the opening may be defined by a first semi-circular portion proximate the movable operator handle, a first U-shaped portion, a second semi-circular portion, which is larger than the first semi-circular portion, and a second U-shaped portion, with the first U-shaped portion opposite the second U-shaped portion, and the first semi-circular portion opposite the second larger semi-circular portion. The first and second U-shaped portions may restrain the generally rectangular cross section, and the first and second semi-circular portions may receive the circular cross section.
As another preferred practice, the first and second U-shaped portions may restrain the generally rectangular cross section with a surface of the shackle of the safety lockout device in a plane blocking movement of the movable operator handle from the first position to the second position thereof. The first and second semi-circular portions may alternatively receive the circular cross section with an edge of a shackle of the padlock offset from such plane toward the movable operator handle and blocking movement of the movable operator handle from the first position to the second position thereof. The offset may be defined by the first semi-circular portion proximate the movable operator handle.
As another aspect of the invention, an electrical switching apparatus is operable with a shackle of a safety lockout device and alternatively operable with a shackle of a padlock. The electrical switching apparatus comprises: a housing; separable contacts; an operating mechanism having a movable operator handle to open and close the separable contacts, the movable operator handle having a first position and a second position; and a handle lock device comprising: a member secured to the housing, a flange on the member disposed alongside the movable operator handle of the operating mechanism, an opening in the flange adapted to receive only one shackle and having a perimeter which includes first opposing portions adapted to receive the first cross section of the shackle of the safety lockout device and to restrain rotation of the first cross section within the opening, with the shackle of the safety lockout device blocking movement of the movable operator handle from the first position to the second position thereof, the perimeter also includes second opposing portions adapted to alternatively receive a second cross section of the shackle of the padlock with the shackle of the padlock blocking movement of the movable operator handle from the first position to the second position thereof.
Preferably, the different second cross section of the shackle of the padlock is a circular cross section, and the perimeter of the opening has a generally circular portion, which is adapted to receive the circular cross section.
According to a preferred practice, the movable operator handle has an end which extends beyond a surface of the housing by a first distance, and the flange of the handle lock device extends beyond the surface of the housing by a second distance which is smaller than the first distance.